﻿<p><em>IfcCurrencyRelationship</em> defines the rate of exchange
that applies between two designated currencies at a particular time
and as published by a particular source.</p>

<p>An <em>IfcCurrencyRelationship</em> is used where there may be a need to reference an <em>IfcCostValue</em> in one currency to an <em>IfcCostValue</em> in another currency. It takes account of fact that currency exchange rates may vary by requiring the recording the date and time of the currency exchange rate used and the source that publishes the rate. There may be many sources and there are different strategies for currency conversion (spot rate, forward buying of currency at a fixed rate).</p>
<p>The source for the currency exchange is defined as an instance of <em>IfcLibraryInformation</em> that includes a name and a URL.</p>

<blockquote class="history">
HISTORY&nbsp; New entity in IFC2x2.</span>
</blockquote>
<blockquote class="change-ifc2x4">
IFC4 CHANGE&nbsp; Subtyped from <em>IfcResourceLevelRelationship</em>, attribute order changed.
</blockquote>